Hi guys i'm new to this but i'm hoping to get some good advice for my dissertation.
Im in my last year in college in Dublin and I will be using a Topcon GLS 1500 TLS for my dissertation, the aim of the dissertation will be to test the measured accuracy of the GLS 1500. Has anyone used the GLS 1500 before? If so would you recommend using it?
Also has anyone any ideas on what the best method for testing the 1) Horizontal accuracy 2) Vertical accuracy and finally 3) The distance accuracy.
Hope you can help 🙂
You need to get copies of the relevant ISO or DIN standards for testing these specifications.
You may also find some useful discussions in prior threads on this forum by searching for related terms.
It might be interesting to do a breakdown of the error sources. How much is due to sighting (by repeated measurement of the same angle), how much is due to tripod twist if you lightly torque the base opposite ways, how much is due to internal variations (by starting the measurement at different rotations of the instrument), etc.
> ... has anyone any ideas on what the best method for testing the 1) Horizontal accuracy 2) Vertical accuracy and finally 3) The distance accuracy.
The California Department of Transportation has done some work in this area. If you google "CALTRANS LASER SCANNER TEST" you will come up with some good academic stuff.
I would think that your testing would involve setting out a grid of targets (I'm thinking mag nails in asphalt) which you determine positions and elevations for to a high degree of accuracy (total station and digital levelling, redundant, and adjusted) and then measuring them with your scanner from various distances under various conditions.
>...Has anyone used the GLS 1500 before? If so would you recommend using it?
No, but I have seen it. A rather large unit compared to the latest Leicas. But if I was shopping I would devote much more attention to the software than the hardware.
Measured Accuracy Compared To What?
And are you in fact measuring accuracy or precision?
I seriously doubt if this is suitable intense matter for a dissertation.
Paul in PA
Natural, instrumental, and personal errors, combined with geometry of the angle of the beam on targets, temperature, sunlight, etc, are going to make this tough to do and come up with anything truly useful. Getting to the bottom of this might take a lot more time than you might think.
When you get your results, what are you actually going to have?
Is this a PhD dissertation? If so, have you gotten this approved? Seems more something from a master's degree thesis at the very most.
Hey guys,
This is not in the US. In the British system a dissertation can refer to an undergraduate final project .
As for the project as mentioned in other messages the best resource in my opinion would be DIN standards and specifications. Alternately, check the Wolf/Ghilani surveying text for some of the statistics, Bomford for some insight into error sources in angle measurements and Ruegar for EDM.
I imagine these resources are available at your school's library.
Good luck,
DMM
